Atlantic salmon (n = 1682) from 27 anadromous river populations and two nonanadromous strains ranging from south-central Maine, USA to northern Spain were genotyped at 12 microsatellite DNA loci. This suite of moderate to highly polymorphic loci revealed 266 alleles (5-37/locus) range-wide. Statistically significant allelic and genotypic heterogeneity was observed across loci between all but one pairwise comparison. Significant isolation by distance was found within and between North American and European populations, indicating reduced gene flow at all geographical scales examined. North American Atlantic salmon populations had fewer alleles, fewer unique alleles (though at a higher frequency) and a shallower phylogenetic structure than European Atlantic salmon populations. We believe these characteristics result from the differing glacial histories of the two continents, as the North American range of Atlantic salmon was glaciated more recently and more uniformly than the European range. Genotypic assignment tests based on maximum-likelihood provided 100% correct classification to continent of origin and averaged nearly 83% correct classification to province of origin across continents. This multilocus method, which may be enhanced with additional polymorphic loci, provides fishery managers the highest degree of correct assignment to management unit of any technique currently available.

No abstract

Accounting for specific alleles can be necessary to prevent the loss of significant biodiversity and ecosystem services.

Spidle. 1993. Colonization, ecology, and population structure of the "quagga" mussel (Bivalvia: Dreissenidaej in the lower Great Lakes. Can. ). Fish. Aquat. Sci. 59: 2305-231 4.An invasive dreissenid mussel given the working name of "quagga" has a present (spring 1993) distribution in the Laurentian Great Lakes from the western basin of Lake Erie to Quebec City. In Lake Erie, quaggas were collected as early as 1989 and now are most common in the eastern basin. In Lakes Erie and Ontario, proportions of quaggas increased with depth and decreasing water temperature. In the eastern basin of Lake Erie, quaggas outnumbered zebra mussel (Dreissena pdymoapkaj by 1 4 to 1 in deeper waters (>29 mj. In Lake Ontario, quaggas were observed at depths as great as 130 rn, and both quagga and zebra mussel were found to survive at depths (>50 rn) where temperatures rarely exceed 5°C. Quaggas were sparse or absent along inland waterways and lakes of New York State. Mean shell size of quagga mussel was larger than that of zebra mussel at sites in the Niagara River, Lake Ontario, and the St. Lawrence River. The largest quaggas (38 mm) were observed in the St. Lawrence River at Cape Vincent.&I ne moule envahissante des groupe des dreissenides, appeiee provisoirement (( quagga a occupe 2i B'heure actuel le ( rintemps 4993) les Grands Lacs depuis le bassin de I'ouest du lac Erie jusqu'h la ville de Qukbec. Dans le lac gi e, des,quaggas ont ete preievees des 1989 et eiles sont maintenant trps courantes dans le bassin de I'est. Dans les lacs Erie et Ontario, la prsporfion de quagga a augment6 avec la profondeur et la baisse de la temperature. Dans [e bassin de I'est du lac Erie, les quaggas sont plus nombreuses que les msesles mebr6es (Baeissena polymorphaj, la proportion sP6tablissant 14 pour 4 en eau profonde (> 29 rn), Dans le lac Ontario, des quaggas ont 6t6 observkes A des prsfondeurs atteignant 130 m; les quaggas et les rs~oules z6brees peuvent suwivre 2i des prsfondeurs (> 50 rn) ob la temperature &passe r?rement 5°C. Les quaggas etaient rares s u absentes le long des vsies navigables de I'intkrieur et dans les lacs de I'Etat de New York. La taille rnoyenne de la coquille des quaggas 6tait supkriekare A celle des rnokales zebrkes sur certains sites du Niagara, du lac Ontario, et du fleuve Saint Laurent.Les quaggas les plus grosses (38 mm) ont et6 observkes dans le fleuve Saint-Laurent au niveau de cap Vincent.